Would the use of silica gel* (say in a sock at the foot end of the bivy) be safe and effective at reducing or eliminating condensation in bivies? Assume your bag isn't excessively warm, but that you are zipped up with just bug netting over your face, or your face and upper half.

I'm just not sure how safe it would be. You're not supposed to breathe the dust, but there appears to be very little dust with this stuff anyway. It's not like clumping cat litter (though it is sometimes used as cat litter - in fact, it's a good way to buy silica gel in bulk).

I don't think it would be practical for multi-day use, since you probably wouldn't have much of a chance to dry it out (and if you did, maybe you'd just dry out the bivy/bag instead, right?). It would add several ounces too, and then weigh even more after absorbing moisture. Still wondering if it would be of any use at all. Seems like the only solutions to avoid moisture is to do away with the WP/B aspect and either have a mostly-netting top, or something that is only water-resistant.

Just one of those curious people thinking of whether/how a WP/B bivy could be made to work ... in the southeast US.


* named "gel", but looks like beads.